Falls from heights are a major problem in both industry and general society when measured in terms of economic losses and human suffering. Given that most of these falls are believed to result from a loss of balance, appropriate strategies to address the problem of falls should focus on improving balance control. Existing research has identified a number of major extrinsic and intrinsic factors involved in the control of balance. Only recently has another intrinsic factor, localized muscle fatigue, been shown to influence balance control. Additional research is needed to further our understanding of how fatigue contributes to loss of balance and falls. To address this need, three projects are proposed that will use laboratory experiments and biomechanical modeling to investigate and mitigate the effects of localized muscle fatigue on balance control. First, experiments will be conducted to examine and quantify the effects of localized muscle fatigue on balance control and the ability to recover from a balance perturbation. Second, a biomechanical model will be developed to quantify balance control strategies in terms of joint torques and to predict the effects of localized fatigue on these parameters. Third, the effectiveness of two interventions aimed at reducing the adverse effects of fatigue on balance control will be determined. Completion of these projects will provide new information concerning factors that can adversely affect balance control and contribute to the development of intervention strategies for fall prevention. Emphasis is also placed on understanding age-related changes in the effect of fatigue on balance control, in light of epidemiological evidence of high fall risks among older workers and demographic trends toward an aging population and workforce.